Why Is the AP Sending BSS Transition Management Queries to Clients?

Why the Answer Is Correct

Optimized Roaming on the WLC makes the AP monitor each client's RSSI (and, in some releases, data rate) and proactively steer below-threshold clients to a better AP using 802.11v BSS Transition Management frames. The over-the-air capture shows precisely that signature: the AP — not the client — originates the BTM query, meaning the roam was network-initiated rather than client-initiated. Disassociation Imminent is only an option flag inside that BTM request that adds a countdown telling the client to move or be disassociated; because it is disabled, it cannot be the source of the query. With Disassociation Imminent off, the remaining WLC feature that generates an unsolicited BTM query is Optimized Roaming, which makes option D the cause. The stem's complaint that clients "are not roaming as expected" fits a network that is forcing roam decisions at a threshold the engineer did not anticipate.

Why the Other Options Are Wrong

Low RSSI check (A) is not a standalone WLAN feature in this context — the RSSI threshold is merely an internal parameter of Optimized Roaming, so naming it describes a component rather than the enabling cause. Fast Transition (B) is 802.11r, which pre-distributes keys and shortens re-authentication to the target AP after a roam decision is made; disabling or enabling it changes roam speed, never whether the AP emits a BTM query. Band Select (C) steers dual-band clients toward 5 GHz by suppressing or delaying 2.4 GHz probe responses during association and has no BTM/802.11v signaling path at all. None of these three options can produce the observed BSS Transition Management query, which is exclusively an 802.11v mechanism.

Community Comment Notes

As Bandito noted, the roaming here happens when it should not, and after researching he concluded that with Disassociation Imminent disabled "another feature which could cause the client to roam is \"Optimized Roaming\"" — a reading that matches the capture evidence. Lakshan__97 argued for option B, but his own description (a flag in the 11v request telling the client it must roam or be disassociated) actually describes Disassociation Imminent inside a BTM frame, i.e. the 802.11v path, not 802.11r. Farhad123 pointed out that a BSS Transition Management query is tied to 802.11v and Optimized Roaming, and cited Cisco's BSS Transition documentation as the reference. The vote split (D far ahead of B) aligns with the protocol analysis rather than with the 802.11r misconception.